Field of the Invention
The present invention relates to a substrate processing apparatus and a substrate processing method for processing a substrate by supplying a fluid to the substrate.
Background Art
In a photolithography process in a semiconductor device manufacturing process, a semiconductor wafer (hereinafter described as a wafer) is supplied with various kinds of chemicals such as resists and the like to process the wafer. A chemical supply device that thus supplies a chemical to process the wafer includes for example a supply source of the chemical, a nozzle discharging the chemical to the wafer, and a supply path connecting the nozzle and the supply source to each other.
Minute foreign matter, such as particles, air bubbles, or the like, may be mixed in the chemical flowing through the above-described supply path. When air bubbles are mixed in a chemical for forming a film on the wafer, such as a resist or the like, the film formed on the wafer may be chipped. When particles are mixed, the particles may function as an unintended mask in an etching process after the photolithography process. When such an abnormality in the film formation and such an abnormality in the etching occur, the yield of the semiconductor device is decreased. Thus, detection of the foreign matter included in the chemical in the above-described supply path has been studied. Japanese Patent Application No. 2004-327638, for example, describes providing a detecting mechanism including an irradiating unit applying laser light and a light receiving unit in a supply path of a chemical supply device, and optically detecting the number of air bubbles in a chemical running through the supply path. In addition, Japanese Patent Application No. 2011-181766 describes a technology in which a sensor for detecting a strain is provided to a supply path and a nozzle of a chemical supply device to detect air bubbles.
A plurality of chemical supply paths may be provided to one chemical supply device. For example, as a chemical supply device, there is a resist coating device that coats a wafer with a resist as a chemical to form a resist film. This device may be provided with a plurality of resist supply paths in order to be able to coat the wafer with one resist selected from a plurality of kinds of resists. Further, the resist coating device may also be provided with a supply path supplying the wafer with a chemical for increasing wettability of the surface of the wafer, as will be described in an embodiment of the invention.
In the device thus including many chemical supply paths, the optical detecting mechanism described in Japanese Patent Application No. 2004-327638 may be provided for each supply path. However, in the case where the detecting mechanism is thus provided for each supply path, because an optical system constituting the detecting mechanism generally has a relatively large size, the chemical supply device is increased in size, and also the manufacturing cost of the device is increased. Japanese Patent Application No. 2011-181766 does not disclose any measure to prevent an increase in size of the chemical supply device and an increase in the manufacturing cost in a case where the chemical supply device has a plurality of supply paths.
The description has been made of problems when foreign matter is mixed in a chemical. However, in various kinds of devices used in the photolithography process, such as the above-described chemical supply device and the like, a gas is supplied to a wafer processing atmosphere. An abnormality may occur also in a case where foreign matter is mixed in the gas, as in the case where foreign matter is mixed in the already described chemicals. A study has therefore been made also of detection of foreign matter in a supply path for supplying the gas to the processing atmosphere.
The present invention has been made on the basis of such circumstances. It is an object of the present invention to provide a technology that can prevent increases in size and manufacturing cost of a substrate processing apparatus including a plurality of supply paths through which fluids to be supplied to a substrate flow, in a case of detecting foreign matter included in the fluids running through the respective supply paths in the apparatus.